1. Field of the Invention
Methods consistent with the present invention relate to packaging broadcast contents which prevents unauthorized copying of broadcast contents transmitted through a digital broadcast receiver and allows only a device having a corresponding content identification to play back the broadcast contents, thereby protecting the broadcast contents.
2. Description of the Related Art
Recently, there has been a surge in the transmission of digital contents using various communications media, such as the Internet, terrestrial networks, cable networks and satellites, and in the sale and rental of digital contents using large-capacity recording media such as compact disks (CDs) and digital versatile discs (DVDs). Accordingly, digital rights management (DRM), which is a solution to protect copyrights of digital contents, is emerging as an important issue. Thus, DRM methods of providing authorized users of a domain with various contents using devices included in the domain are actively being investigated.
Digital broadcast contents are transmitted from contents providers to users. Users are authorized to use digital broadcast contents only after they obtain the rights to use the digital broadcast contents. Thus, digital broadcast contents must be protected from unauthorized users.
The U.S. Federal Communications Commission (FCC) is considering a requirement to add a one-bit broadcast flag (BF) to high definition (HD)-grade contents digitally broadcast within the U.S. to prohibit the indiscriminate redistribution of digital terrestrial broadcast programs. In other words, the FCC intends to promote the safe use of digital broadcast contents using a technology that prevents unauthorized users from using digital broadcast contents when a BF included in the digital broadcast contents is on.
FIG. 1 is a conventional table showing operations which are allowed or not allowed according to a BF. Referring to FIG. 1, if a copy control bit included in broadcast contents is a BF, permission to store or copy the broadcast contents is given according to the type of the BF.
More specifically, when the BF is off, storing and copying of the digital broadcast contents are permitted. When the BF is on, the broadcast contents can be stored only after being encrypted, and can or cannot be copied. In FIG. 1, “O” indicates operations allowed and “X” indicates operations not allowed.
In 2005, the Open Cable standard is set to become the next-generation cable broadcast standard of the U.S. The Open Cable standard makes it compulsory to use copy control information (CCI) to control or restrict the storing or copying of contents received. CCI is two-bit control information which controls the copying of cable broadcast contents by indicating “copy free” (00), “copy once” (01), “copy no more” (10), and “copy never” (11).
FIG. 2 is another conventional table showing operations which are allowed or not allowed according to CCI. Referring to FIG. 2, if a copy control bit included in broadcast contents is CCI, permission to store and/or copy the broadcast contents is given according to the type of the CCI.
More specifically, when the CCI is “copy free,” broadcast contents can be stored and copied. When the CCI is “copy once,” the broadcast contents can only be stored. When the CCI is “copy never,” it is not allowed to store the broadcast contents, and when the CCI is “copy no more,” it is not allowed to copy the broadcast contents. When the CCI is “copy free,” the broadcast contents can be stored without being encrypted, and when the CCI is “copy once,” the broadcast contents can be stored after being encrypted. In FIG. 2, “O” indicates operations which are allowed and “X” indicates operations which are not allowed.
As described above, there is a growing need for restricting the unlimited storing and copying of digital broadcast contents. However, a mechanism for packaging and storing digital broadcast contents and information regarding rules for using digital broadcast contents has not been suggested.